Separable ladder



Feb. 1, 1955 H. F. TREVINO SEPARABLE LADDER Filed July 10. 1950 w an oak Mme W .WEH REM& mRoR N m W E MMF q fi mm H R e M Hm a a m u m OJ 3 w United States Patent SEPARABLE LADDER Herbert F. Trevino, South Gate, Calif.

Application July 10, 1950, Serial No. 172,951

2 Claims. (Cl. 228-40) This invention relates to ladders and, more particularly, to a ladder comprised of a plurality of separable component parts, said separable component parts being adapted to be added to or separated from one another to increase or decrease the range and length of the ladder.

The principles of my invention may be applied with equally desirable results to ladders having rigid side members spacing and supporting the rungs thereof, but, for purposes of illustration, my invention will be primarily described as embodied in a chain ladder, that is, a ladder having side members constituted by lengths of chain spacing and supporting the rungs.

In many large manufacturing establishments, and particularly in such plants as refineries and chemical plants, there is a constant need for ladders of different lengths which are utilized by workmen in cleaning out and otherwise servicing storage tanks, fractionating and bubble towers, and the like. In a large plant the range of different sizes and the number of such ladders which must be maintained in stock in the toolroom are a considerable factor in the tool room inventory. For instance, in cleaning fractionating towers, ladders as long as 100 ft. may be necessary while in cleaning relatively small storage tanks a ladder ft. in length may be satisfactory.

It is, therefore, a primary object of my invention to provide a ladder which consists of a plurality of separable component parts which can be added to or subtracted from one another to form a ladder of greater or less size and range.

Another object of my invention is the provision of a ladder of the aforementioned type which includes a plurality of connectors adapted to maintain the side member elements of the ladder in operative relationship with one another.

An additional object of my invention is the provision of a ladder of the aforementioned type in which the connectors include separable segments adapted to engage each other and said segments are provided with interengageable faces adapted to retain said segments in operative relationship with one another.

Another object of my invention is the provision of a ladder in which the side members are constituted by a plurality of individual side member elements of identical length, said side members being adapted to be added to or superimposed one upon the other at either side of the ladder to form a ladder of desired length.

An additional object of my invention is the provision of a ladder of the aforementioned type in which each of the side member elements has attached to the opposite ends thereof a connectorsegment adapted to engage a connector segment upon the adjacent end of another side member element to maintain the side member elements in operative relationship with one another.

Another object of my invention is the provision of a ladder having side members constituted by a plurality of side member elements of identical length, said side member elements being maintained in operative relationship with one another by connector means and said ladder also including a plurality of rungs whose spacing is determined by the length of said side member elements, said rungs having receptacle means adapted to receive said connector means to maintain the individual segments of said connector means in operative engagement with one another.

Another object of my invention is the provision in a ladder of the aforementioned type of rungs having receptacles formed in the opposite ends thereof adapted to receive the connector means of said ladder and to maintain the individual segments of the connector means in operative engagement with each other.

An additional object of my invention is the provision of a ladder of the aforementioned type which includes rungs having receptacles formed therein adapted to receive the connector means of said ladder and provided with retainer means adapted to retain said connector means within said receptacles.

A further object of my invention is the provision in a ladder of the aforementioned type of a plurality of rungs, each of said rungs being constituted by a tubular element and the ends of said tubular elements constituting receptacles for the reception of the connector means of said ladder.

Another object of my invention is the provision in a ladder of the aforementioned type of rungs constituted by a plurality of tubular elements having ends serving as receptacles for the connector means of the ladder, said ends being provided with retainer means adapted to maintain the connector means of the ladder within said ends.

An additional object of my invention is the provision in a ladder of the aforementioned type of side member elements constituted by a plurality of links adapted to impart flexibility to the side member elements to permit the ladder to be stored upon a reel or similar storage means.

An additional object of my invention is the provision in a ladder of the aforementioned type of rigid side member elements having formed upon opposite ends thereof or fastened thereto, connector segments adapted to engage connector segments upon adjacent ends of similarly formed side member elements.

A further object of my invention is the provision of a ladder of the aforementioned type, the component parts of which can be readily assembled and disassembled, which is of inherently sturdy construction and which can be manufactured and sold at relatively low cost.

Other objects and advantages of my invention will be apparent from the following specification and the accompanying drawing, which is for the purpose of illustration only, and in which:

Fig. l is an elevational view of a portion of a ladder constructed in accordance with my invention;

Fig. 2 is a fragmentary, enlarged, partly sectional view taken on the broken line AA of Fig. 1;

Fig. 3 is a fragmentary, enlarged, partly sectional view taken on the broken line B-B of Fig. 1;

Fig. 4 is an enlarged, partly sectional view taken on the broken line C-C of Fig. 2;

Fig. 5 shows a suspension means for the ladder of my invention; and

Fig. 6 is an alternative embodiment of a side member element constructed in accordance with my invention.

Referring to the drawing, and particularly to Fig. 1 thereof, 1 show a ladder 10 which includes side members 11 disposed at opposite sides of the ladder and composed of a plurality of side member elements 12. The side member elements 12, in the present embodiment of my invention, are constituted by individual and identical lengths of chain 13, said lengths of chain consisting of a plurality of links 14.

Interposed between the adjacent ends of the side member elements 12 and connected thereto in a manner to be more explicitly described below, are connector means 15, said connector means being constituted by identically shaped and oppositely disposed connector segments 17 and 18. The connector segments 17 and 18 have, respectively, dentiform inter-engaging surfaces 19' and 20. The teeth 22 and 23 of the dentiform inter-engaging surfaces 19 and 20 are angularly inclined and arranged about the vertical axis of the connector means 15 so that vertical loads imposed upon the connector 15 will be transmitted from one segment to the other through the teeth 22 an 23.

The peripheries of the connector segments 17 and 18 are of arcuate configuration and when said segments are placed in interengagement with each other to constitute the connector means 15, the connector means presents a substantially cylindrical configuration for a purpose which will be described in greater detail below.

The connector segments 17 and 18 are provided, respectively, with projecting connector portions 25 and 26 which have formed therein apertures 27 and 28 engageable by the lowermost and uppermost links 14 of adjacent side member elements 12.

Thus, the connector means 15 and, more particularly, the inter-engageable segments 17 and 18 thereof serve to join together adjacent ends of the side member elements 12 and to transmit from one side member to another any load imposed upon the ladder 10.

The ladder is provided with transversely positioned rungs 28 which are constituted by tubular elements 29, such as lengths of pipe. The end portions 30 of the tubular elements 29 serve as cylindrical receptacles 31 adapted to receive the connector means 15, the cylindrical configurations of the interiors of the receptacles 31 conforming substantially to the cylindrical peripheries of the connector means 15. Thus, the receptacles 31 serve to maintain the separable and inter-engageable seg ments 17 and 18 of the connector means in operative engagement and prevent the inadvertent disengagement of one of said segments from the other.

Slots 33 and 34 are cut into the ends 30 of the tubular element 29 and are adapted, respectively, to receive the connecting portions and 26 of the segments 17 and 18 of the connector means 15. The slots 33 and 34 thus permit the connector means to protrude from the interiors of the receptacles 31 and facilitate the engagement of the segments 17 and 18 by adjacent ends of the side member elements 12. In addition, the slots 33 and 34 by their engagement with the inner edges of the connecting portions 25 and 26 of the segments 17 and 18 prevent the lateral shifting of the segments with reference to each other by limiting the lateral movement of said segments within the receptacles 31.

The opposite ends of the tubular elements 29 are threaded, as at 36, said threads being adapted to be engaged by retainer means 38 constituted, in the present embodiment of my invention, by conventional pipe caps 39. The leading edges 40 of the pipe caps 39, as best shown in Fig. 4 of the drawing, are carried inwardly upon the threaded portions 36 of the tubular elements 29 until they contact the connecting portions 25 and 26 of the connector segments 17 and 18 at the edges on one side thereof. When this contact is accomplished, the connecting portions are securely positioned in the slots 33 and 34 and the lateral or rotational movement of the connecting portions 25 and 26 and their associated connector segments 17 and 18 is prevented.

It is intended that a length of ladder 10 sufficient to handle the maximum demand for varying lengths of ladders be maintained and stored upon a reel in the toolroom of a refinery or similar plant. Since the side member elements 12 are of identical length, in the present instance one foot, it is possible for an attendant to remove a required number of feet of ladder from the reel by merely counting the number of rungs in the ladder.

The manner in which a length of ladder is separated from the ladder on the reel is as follows: the end caps 39 are unthreaded from the end portions of a tubular element 29 and one of the connector segments 18 is disengaged from its companion segment 17, in each end of the tubular element 29, by moving it laterally toward the open end of the tubular element 29. The caps 39 are then rethreaded upon the end portions 30 of the tubular element 29. The remaining connector elements 17, as best shown in Figs. 1 and 2 of the drawing, remain in the receptacles 31 with their arcuate peripheries in intimate contact with the walls of the receptacles 31.

In this manner, a selected length of ladder can be removed from the supply on the reel and the necessity for maintaining a large supply of different lengths of ladder is eliminated.

When it is desired to return the length of ladder to its place upon the reel, the end caps 39 on the tubular member 29 are removed and the connector segments 18 are inserted into the receptacles 31 and into engagement with the segments 17.

It should be noted that, when the component parts of the ladder 10 are in assembled relationship, the weight of an individual upon the rungs 28 of the ladder is transmitted from the rungs to the connector means 15 whence it is transmitted through the side member elements 12. Thus, most of the load is ultimately borne Uil upon the side member elements 12 and not upon the rungs themselves, preventing the possible failure of the rungs at the ends thereof.

An alternative embodiment of the side member element of my invention is shown in Fig. 6 of the drawing and is exemplified as a side member element having an intermediate rigid portion 46 to the opposite ends of which are fastened connector means segments 47 and 48. When a plurality of the side member elements 45 are arranged in operative relationship with one another by the inter-engagement of the connector means segments 47 and 48 with other like segments and said segments are inserted in receptacles 31 in the ends of the tubular elements 29, a rigid ladder construction is provided.

Thus, a supply of side member elements 45, rungs 28, and caps 39 may be kept in a suitable container and a rigid ladder of the desired length assembled therefrom whenever the need for such a ladder arises. In this manner, the need for storing rigid ladders for varymg lengths and of relatively bulky size is eliminated. Therefore, it is obvious that the principles of my invention can be applied with equal effectiveness to both flexible and rigid ladders.

When utilizing flexible ladders 10 constructed in accordance with my invention, it is frequently necessary to provide some means for suspending the ladders from the structure upon or in which they are utilized. A suspension means for such ladders is provided by my invention and includes, as best shown in Fig. 5, a grapple hook 49 having affixed to the lower end thereof by means of a chain or similar flexible element 50 a connector means segment 51. After a desired length of flexible ladder 10 has been removed from the previously mentioned storage reel, the connector segments 51 can be inserted in one end of the ladder into engagement with the connector segments in the receptacles 31 and retained therein by the caps 39. Of course, it is intended that two of the suspension means be utilized, one at each side of the end of the ladder 10.

I thus provide by my invention a ladder which consists of a plurality of separable members adapted to be assembled and disassembled with relative ease to form ladders of varying lengths. The principles of my invention are equally applicable to rigid and flexible ladders. Because of the demountable nature of the ele ments of my invention, they can readily be stored in a relatively small space, this being particularly true of a rigid ladder constructed in accordance with my invention. On the other hand, with flexible ladders constructed in accordance with my invention, a complete length of flexible ladder sufficient when distributed in varying lengths to satisfy the needs of the particular organization by which it is utilized can be stored on one or more reels, thus reducing the storage problem occasioned by the necessity for maintaining different lengths of flexible ladder for difierent uses in the plant.

I claim as my invention:

1. In a ladder, the combination of: a plurality of tubular rungs, each of said rungs having slots formed in each end thereof and communicating with the intenor of such rung; a pair of side member elements oppositely disposed at each end of each rung and extendmg between adjacent rungs; and separable interengaging connectors receivable in each end of each rung and having connecting portions protruding through said slots in said end in diametrically opposite directions and engaging adjacent ends of the respective side member elements to maintain said rungs connected to said side member elements.

2. In combination in a ladder: a plurality of elongated rungs having hollow ends; a pair of side members oppositely disposed at each end of each rung and separably connected to the opposite ends of each rung; connectors attached to the opposite ends of each side member and disposed in each of the hollow ends of the respective rungs, the connectors of the adjacent side members of each pair separably interlocking to form a pair of connectors within the respective hollow end and to constitute an enlargement filling the respective hollow end and generally conforming in configuration with the configuration of the interior walls of said hollow end for retention therein, each pair of interlocking connectors being insertable into the respective open hollow end of the respective rung for said retention; and means secur- 5 6 ilnglleach giair ofhifitefi-locking cgnnefitors inbthe respective References Cited in the file of this patent o ow en ,eac o ow endo eac rung eing diametrically slotted to communicate with the hollow interior UNITED STATES PATENTS thereof and each connector having a portion projecting 628,824 Maier July 11, 1899 through the adjacent slot and attached to the respective 5 836,432 Bryant Nov. 20, 1906 side member. 1,520,414 Hamilton Dec. 23, 1924 1,725,367 Mowry Aug. 20, 1929 

